* { box-sizing: border-box; }
body { margin: 0; font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji"; background: #f7f7fb; color: #111827; }
.container { max-width: 720px; margin: 40px auto; background: #fff; padding: 24px; border-radius: 12px; box-shadow: 0 10px 25px -10px rgba(0,0,0,.1), 0 1px 4px rgba(0,0,0,.06); }
label { display: block; margin-bottom: 12px; font-weight: 600; }
input { width: 100%; padding: 10px 12px; margin-top: 6px; border: 1px solid #e5e7eb; border-radius: 8px; }
button { appearance: none; border: none; background: #2563eb; color: #fff; padding: 10px 16px; border-radius: 8px; font-weight: 600; cursor: pointer; }
button:hover { background: #1d4ed8; }
.header { display: flex; align-items: center; justify-content: space-between; }
.error { color: #b91c1c; background: #fee2e2; padding: 8px 12px; border-radius: 8px; margin-bottom: 12px; }
code { background: #f3f4f6; padding: 2px 6px; border-radius: 6px; }